The present invention relates to a heating apparatus for liquids or gases wherein the viscosity rises significantly at a lower temperature or wherein maintenance at a proper temperature is necessary for a certain purpose.
Such fluids as described require heating to a temperature higher than a fixed value in the storage tank, on the way through transporting pipe line, etc.
The most frequently used equipment among the conventional heating equipments is one shown in FIG. 11. In this conventional equipment, a heat transfer pipe 8 made from steel pipe is provided inside the storage tank 9 in a way that one end is protruded from said tank 9 and an inner cylinder 82 filled with rock wool 81 is inserted into this heat transfer pipe 8. On the outer circumference of this inner cylinder 82, MI cable (nonadhering insulated heating cable) 83 is wound spirally and densely and, in the space between MI cable 83 and heat transfer pipe 8, alumina 84 is filled to make the heat resistance low between the cable 83 and the heat transfer pipe 8. When charging MI cable 83 with electricity, Joule heat generated is transmitted to the oils in storage tank through the filled layer of alumina 84 and the heat transfer pipe 8. Numeral 91 is a flange for fitting and numeral 85 is a connection box in FIG. 11.
With the heating equipment above, the handling is easy at the time of running, but, at the time of breakdown, the whole equipment mainly composed of heat transfer pipe 8 must be exchanged. Since all of the contents of the tank must be removed for the exchange of the heater, there was a problem in coping with the breakdown. Moreover, it is the present status that, even if alumina is filled between the heat transfer pipe and MI cable, the heat resistance is still high resulting in that the temperature of MI cable becomes high and the limit on heating temperature of the heating apparatus is considerably lower than the tolerance temperature of MI cable. Furthermore, there were problems that the output of the heating apparatus and the length of heat transfer pipe are restricted by the output and the length of MI cable making the apparatus unsuitable for the storage tank of large capacity, and so on.
The purpose of the invention is to improve the aforementioned problems of the conventional heating, that is, to provide a heating apparatus wherein the maintenance work at the time of breakdown etc. is simple, the output and heating temperature can be established without any restriction by the cable insulation etc., the apparatus can be installed to the center of the container even when heating tanks of large capacity and, at the same time, the equipment can be installed in low cost.